February, '15] 



CHAPMAN AND GLASER: WILT DISEASE 



143 



time though many were dead or d^^ing. The next day a typical case 

 of wilt developed in one of the stock trays in the laboratory. The 

 caterpillar was flaccid, hung by its prolegs and the skin broke at the 

 slightest touch. A thin grajdsh liquid oozed out which proved on 

 examination to contain almost pure polyhedra. Other cases of wilt 

 developed in these trays from time to time. A number of deaths 

 were also caused by bacterial infection as the post-mortem examina- 

 tions showed. 



We have had shipments of army worms from Nantasket, Mass., 

 Hagerstown, Md., and Norfolk, Ya. That the wilt was present in 

 all of these places was shown by the typical cases of wilt in the ship- 

 ping boxes at the time of their arrival at the laboratory from these 

 places. J. A. Hyslop, of the Bureau of Entomologj^, who is located 

 in Maryland, shipped 350 caterpillars (isolated in separate pill boxes) 

 at one time. These were from seven different broods. Brood number 

 five had 52 caterpillars, 50 of which were dead when we received the 

 shipment. The remaining two died before the next day. There were 

 also 30 dead in the other six broods, making a total of 82 dead with 

 wilt out of 350 caterpillars. 



Prof. Franklin Sherman, Jr., of North Carolina, recently informed 

 us, after we had described the wilt to him, that some such malady did a 

 great deal towards checking an outbreak of the army worm in North 

 Carolina the past summer. 



We have been more recently informed concerning the appearance 

 of the wilt in two other outbreaks of the army worm, one in Illinois 

 and the other in Oklahoma. 



The Tussock Moth 



During 1911 we made observations on the Tussock moth on Boston 

 Common. A disease appeared among the second generation cater- 

 pillars which almost completely destroyed them. It had all of the 

 external appearances of wilt and was so considered by us at that time^ 

 though no microscopical examination of the caterpillars was made. 



The Tussock moth has been so scarce in New England since then that 

 we have been unable to verify the observations of 1911.^ The abun- 



1 Since the above was written we found some of the dried Tussock moth caterpillars 

 taken on Boston Common, Aug., 1911, which had been stored with other insect 

 materials. We examined them and the polyhedra were found to be plentiful and as 

 fresh in appearance as though they came from caterpillars of the past season. 



December 22, 1914, we received a letter from J. S. Houser, Associate Entomologist 

 at the Agricultural Experiment Station, Wooster, Ohio, in which he says of 0. leuco- 

 stigma: "The accompanying photograph was taken July 7 at the time the cater- 

 pillars were supposed to be transforming to the pupal stage. The plot was practically 

 defohated, and for this reason attracted my attention; but much to my surprise I was 



